"Runners on first and second right there, you've got to get them over," said Harper, who made the decision to bunt on his own. "He actually hung me a curve ball I probably could have drove, but I was lucky enough to get one down, get those guys over."

Rendon grounded to short, scoring Hairston. Ryan Zimmerman (3-for-5) followed with a grounder up the middle. Shortstop Omar Quintanilla fielded the ball behind second and threw to first. Zimmerman was safe, and Span, who never stopped running, scored from second with the tying run.

Werth followed with a double to right-center, scoring Zimmerman from first with the lead run.

"He had the most unbelievable BP today," Johnson said of Werth. "He's been swinging the bat good. He's driven."

Washington had 16 hits, but stranded nine base runners in the first six innings.

"We finally got some hits with runners out there," Johnson said. "It took a while."

Erik Davis (1-0) pitched a scoreless eighth inning for his first major league win. Rafael Soriano pitched the ninth for his 36th save and the Mets had to settle for two-out-of-three.

"Anytime you can win a series, it's big. This time of the year, you've got to win as many as you can," manager Terry Collins said. "Certainly, this is one we're going to look back on and kick ourselves a little bit for letting it get away."

Trailing 5-2, the Nationals got an RBI single from Wilson Ramos off reliever Scott Atchison in the seventh after Atchison threw two wild pitches with a man on first.

Matt den Dekker hit his first big-league homer for the Mets, who led 3-0 after two innings.

Nationals starter Ross Ohlendorf lasted just five innings, allowing four runs on nine hits. He walked one and didn't strike out a batter.

New York's Jonathon Niese pitched around 10 hits and two walks, allowing just two runs. After he walked Harper with two outs in the sixth, Niese appeared in some discomfort and was taken out of the game. The Mets later announced he suffered a left calf cramp.

"A lot of things didn't go our way tonight," Niese said. "A lot of broken-bat hits, ground-ball hits that got through the hole. And that's kind of how it goes sometimes, a game can unravel in a hurry."

Eric Young and Daniel Murphy doubled in the first to give the Mets a 1-0 lead. Murphy later scored on Lucas Duda's single.

With one out in the second, den Dekker made it 3-0 when he sent an Ohlendorf fastball into the second deck in right-center.

Washington got one back in the second. Werth doubled, went to third on a groundout and scored on a two-out single by Tyler Moore.

The Nationals pulled to within 3-2 in the fourth.

Ian Desmond and Ramos singled. After Desmond went to third on a fly out, Hairston singled up the middle, scoring Desmond.

New York responded in the fifth as Murphy singled home Niese, who doubled.